Interpretive Summary: New methods of insect control under development today include the use of naturally-occurring substances that are either lethal to, or alter the normal development of insects. Those natural substances that are protein in composition are often tested in transgenic organisms, where the gene for the natural substance is engineered into a plant or a microbial organism to oprotect a crop from damage by the insect. The continuation of these methods will require the discovery of new substances that affect the development of pest insects. This study investigated the response of different insects to the venom from a wasp that normally parasitizes a weevil. The tests included caterpillars, weevils, and beetles. The venom stopped the development of all insects that were tested. The chemical qualities of the venom suggest that it may be a good candidate for use in the construction of transgenic organisms. The ability of the venom to stop pdevelopment of a wide range of insects increases the potential value of th venom in commercial applications to control insects that are pests of agricultural crops.

Technical Abstract:
We tested Hypera exima (LeConte), a natural host, and factitious insect hosts for their physiological responses to stinging by the gregarious ectoparasite, Necremnus breviramulus Gahan, and observed hosts injected with an extract of the venom gland tissue dissected from the lower reproductive tract of the female parasite. Tests included its coleopteran host and other species of Coleoptera and Lepidoptera not previously recorded as hosts. The arrestment of development produced by N. breviramulus was expressed in the natural host and in all insects tested outside the natural host range of the parasite. Arrestment activity was found to be associated with the aqueous extract of the venom apparatus and the response was shown to be dose-dependent. The protein composition of the venom from N. breviramulus differed from other eulophids, and did not contain the ecdysis-arresting-protein found in Euplectrus spp. The difference in venom proteins may account for the different physiological effects and host range of these eulophid parasites.